The Death of the Hockey Stick?

People who have been following the climate debate closely know that one of the most controversial and key elements of the controversy is the so-called “hockey stick” -- a graph of supposed global temperature over the past centuries that ostensibly shows a dramatic increase in average temperature in the last century or so (the upward swoop of the graph at that point is the business end of the stick, with regard to the puck). It vaulted its inventor, Michael Mann of Penn State University, to climate stardom, with associated acclaim and government grants, when he first presented it in the late '90s. It was the visual basis of much of the hysteria in recent years, from Al Gore’s Oscar-winning crockumentary to bogus reports from the UN’s Intergovernmental Panel on Climate Change (IPCC).

Unfortunately for those promoting the theory (and the potentially economically catastrophic policy recommendations supposedly supported by it), recent events indicate that the last basis of scientific support for the hockey stick may be crumbling. But to understand this, a little background is necessary.

Ultimately, in addition to Mann’s claim for the dramatic recent uptick (which we are supposed to presume was a result of the late industrial revolution and equally dramatic increase in carbon dioxide into the atmosphere as a result of the liberation of carbon from burning long-buried fossil fuels), Keith Briffa of the Climate Research Unit (CRU) at the University of East Anglia in England controversially declared, based on Eurasian data, that the well-documented Medieval Warm Period (MWP), from around 950 to 1250 CE -- the European Middle Ages -- didn’t actually exist.

This claim was important, if not essential, to Mann’s thesis, because his initial formulation only went back to 1400, the beginning of the so-called Little Ice Age. Critics of the theory thus argued immediately upon its presentation that it shouldn’t be surprising that the earth was warming now, given that we are still coming out of it, and that the medieval warming in the absence of late Carolingian SUVs and coal plants argued that the climate naturally cycled, with no need to invoke Demon Carbon. That is to say, to the degree that the hockey stick has a blade in the twentieth century, it would have another a millennium ago.

The theory has continued to take blows over the years since it was first presented. About a decade ago, a paper was published by Willie Soon and Sallie Baliunis claiming that there was good evidence that both the (still extant) MWP and current warming were driven by solar activity rather than carbon emissions. But these initial attacks were beaten back by the climate mafia (as we now know from the leaked emails between Mann and his partners in crime in East Anglia from two and a half years ago). The real damage came when a retired Canadian mining engineer, Steve McIntyre, and a professor at the University of Guelph, Ross McKitrick, started digging into Mann’s methodology, and found flaws in both his statistical analysis and data interpretation, and published a paper describing them in Geophysical Research Letters in 2005. They showed that Mann’s methodology would generate a hockey stick almost independently of the data input, by feeding it spectral noise. Later, Internet satirist (and apparent statistician by day) Iowahawk provided a primer on how to create a hockey stick at home, using a standard spreadsheet program.

Defenders of the theory have long claimed that even if there are problems with Mann’s method or data set, we have independent results from other research, such as that at the CRU, that confirm it. But this was a point of contention. In addition to the unscientific behavior in attempting to silence critics and keep them from publishing, we also know that the climate “scientists” had been withholding data that would help to resolve the controversy (more unscientific behavior, because it makes it difficult or impossible to replicate claimed results, and behavior that continues to the present day by the University of Virginia), even in the face of numerous Freedom of Information requests, on both sides of the Atlantic.

To no avail, McIntyre had been requesting data for years from Briffa, who had claimed to have independent Eurasian tree-ring analysis that confirmed Mann’s results, from a data set called the Polar Urals (Mann’s work was based on ancient California bristlecone pine trees). Unfortunately, paleoclimatologists had discovered that the Polar Urals data didn’t actually support the disappearance of the MWP, so they were in search of another Eurasian data set that would, and they found one called Yamal, gathered and published in 2002 by two Russian scientists.